THE MAST CELLS 



Weidenreich (1908) and Proscher (1909) came to regard the blood mast cell as 

 a degenerative lymphocyte, the cytoplasmic bodies being alleged to represent 

 nuclear extrusions or a mucoid degeneration of the protoplasm. Thereafter, 

 Pappenheim's pupils, Bennachio (1911), Kardos (1911) and St. Szecsi (Pappen- 

 heim and St. Szecsi, 1912), persistently failed to find precursors for the blood 

 mast cells in the marrow of guinea pig and rabbit, ignoring completely the 

 excellent point made by Ferrata (1912) in his book, that a high basophil count 

 occurs in man in chronic myeloid leukaemia, not in chronic lymphatic 

 leukaemia as it should if the theories of Pappenheim and Weidenreich were 

 valid. 



Outstanding in this period of confusion over the identity of the blood mast 

 cell is the high quality of the contributions of Maximow of St. Petersburg. 

 Maximow (1906) had previously stressed the abundance of mast cells in the 

 blood of the rabbit in contrast to the paucity of its tissue mast cells (Westphal, 

 1891 ). Four years later Maximow (1910) returned to this subject and presented 

 substantial evidence not only for the myeloid origin of the blood mast cells 

 in the rabbit but also for a similar origin of the mast leucocytes in guinea pig, 

 cat and rat. In 1913 he and Downey simultaneously published papers calculated 

 to end the controversy for any impartial observer. Maximow reviewed his 

 previous evidence, added fresh findings regarding the mast leucocytes in the dog 

 and searched normal marrow in man with such persistence that eventually he 

 was able to depict mast myelocytes in mitosis. The results of Downey's 

 research on the guinea pig led him to declare with like conviction (p. 137) that, 

 providing an adequate histological technique is used, 'the mast leucocytes 

 of the animal are so definite and characteristic that they can be identified from 

 the moment of their first appearance in the bone marrow'. Finally, Downey's 

 pupil, Ringoen (1919, 1923), using a fixative actually introduced by one of 

 Pappenheim's own students, St. Szecsi (1913), corroborated the myeloid 

 origin of the mast leucocytes in both rabbit and guinea pig, the accumulated 

 evidence of the period being critically evaluated by Maximow (1924). 



In his summary Maximow (1924) reviews the status of the blood mast cell 

 throughout the evolutionary scale, pointing out as we have already observed 

 in discussing the tissue mast cell that it is only with the evolution of the bone 

 marrow that partition occurs in the production of mast cells. The mast cells 

 of lower organisms are derived from cells of the fixed mesenchyme or from 

 undifferentiated circulating precursors which lodge in the tissues and there 

 elaborate their characteristic granules (cf. Kollman, 1908; Michels, 1923; 

 Wigglesworth, 1956). Tissue mast cells in higher organisms continue to arise 

 and to remain in the old haemopoietic centres and a new type of cell, the mast 

 leucocyte develops in parallel with the other members of the myeloid series 

 and, with them, finds its way from the marrow into the blood stream. In 



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